There has hitherto been known a technique in which a thin layer of powder corresponding to each of cross-sections obtained by cutting a subject to be three-dimensionally shaped at a plurality of parallel planes is bound with a binder, and the thus bound thin layer is successively laminated to prepare a shaped object as a three-dimensional model of the subject to be shaped.
Such a technique can be employed to applications of rapid prototyping and design confirmation. In recent years, a mode utilizing an inkjet, which is cheap and high-speed and is adaptive to color modeling preparation, is proposed and disclosed in, for example, Patent Document 1. A specific process of the three-dimensional shaping is described below.
First of all, a thin layer of powder is uniformly spread on the flat surface by means of a blade mechanism, and an inkjet nozzle head is scanned on a prescribed region of the thin layer of powder to discharge a binder. The powder material on the region where the binder has been discharged is subjected to necessary operation to become in the bound state and bind to an already formed lower layer. A powder layer is successively formed thereon, and the step of discharging a binder is repeated until the whole of a shaped object is completed. Finally, since in a region to which the binder has not adhered, the powders are in the individually independent and unbound state, when the shaped object is taken out from the device, the powder can be easily removed, whereby the shaped object can be separated. A desired three-dimensionally shaped object can be produced by the foregoing operations.
Also, in a similar method, a technique in which binders are colored in yellow (Y), magenta (M) and cyan (Y), thereby painting the three-dimensionally shaped object and enhancing the binding strength is disclosed, for example, in Patent Document 2.
However, it is the present state that according to the foregoing measures, the shaped object does not reach the satisfactory level with respect to characteristics (texture and color) as compared with the desired material. In particular, it is considered impossible to produce a three-dimensionally shaped object requiring transparent feeling due to a difference in property between the powder and the binder and the presence of voids formed by the use of the powder according to the conventional methods. Further, in order to impart smoothness to the surface, since overcoating and polishing treatments must be assisted by hands, it requires time and costs.
Also, according to painting by hands, it is ordinarily difficult to surely draw a desired pattern or the like at a prescribed position of a three-dimensionally shaped object.
On the other hand, since the three-dimensionally shaped object immediately after the production is formed relying on only a binding force of the binder, its strength may be possibly weak, resulting in collapse depending upon the handling method of the three-dimensionally shaped object. Thus, for increasing the strength, impregnation of a resin or wax into the spaces between powder particles of the three-dimensionally shaped object after the production has hitherto been conducted. However, such a step requires labors and time.
Patent Document 1: Japanese Patent No. 2,729,110
Patent Document 2: JP-A-2001-150556 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”)